Outlook High CPU Usage - Solved

I was having some performance issues with Outlook 2007.  When running idle, it was consuming around 20-30% CPU.  I know that Outlook is no small app but 20-30% CPU when idle, c'mon!

Trying to figure out what was wrong, I made sure I downloaded all the performance patches and I applied Office SP1 but still experienced a high CPU usage.

One day, I had the idea to disable all the non essential add-ins.  Looks like with every software application comes with an Outlook add-in.  Why do I need a SnagIt add-ins in Outlook?  Why do I need a MindManager add-in?  Nuisance if you ask me.

Guess what?  After disabling these add-ins, Outlook CPU usage dropped to 0% with peaks at 2-4%!!!

So how do you disable Outlook ad-ins?  In the Tools menu, select Trust Center.

Click on the Add-ins tab on the left of the screen and in the lower portion, select Com Add-ins from the drop down and click Go.

You can then uncheck non essential add-ins.


  • hmm strange.. I tried the same, but still my cpu usage is about 20 to 30%.. so my laptop fan goes crazy.

  • Disabling SnagIt dropped my Outlook idle CPU usage from 35% to 2-6% Much better! :-)

    Thanks for the advise

  • It did not help with my PC. CPU usage goes high randomly up to 100% and hangs my PC. In addition, I cant kill outlook.exe from task manager!!!

  • Disabling iTunes Outlook AddIn helped in my case.. Thanks

  • cpu was getting 50% - 60% usage. found i had 2 outlook pst files being used at the same time. removed one of them and it worked great.

  • Thank you for the well thought out and presented instructions on this issue. Disabling Plaxo, iTunes and Xobni reduced by Outlook 07 CPU usage from an astonishing 99% to 2% with manageble spikes in the 30 - 50% range during heavy operations. I kept Linked-in as an add-in which seems work well.

  • Hi

    Just wanted to say thanks for this - I had been experiencing major issues with this and had no idea how to solve it.

    It worked first time - thanks again for such clear instructions


  • User's PC was running outlook process at 97% of CPU. Found this problem to be a 92mb file in the outbox on a user's PC. Deleted it, problem solved.

  • Guy,

    the instructions you gave were outlined perfectly and I have followed all of the steps outlined from some of the other memebers who posted as well. I however still have an issue. If soemthing comes else comes to mind and would kindly share your thoughts that would be great.


  • I had a similar problem with 60-80% cpu usage. I reformatted, reinstalled from the recovery CD and still had the same high cpu usage. My problem turned out to be my internal AR5005 wireless antenna. Searched for the newest drivers and the problem went away.

  • guys - this is a life saver! I was having problem where it seems to run out of memory..my email in the inbox the fonts was getting strange formatting look, bold and another font used is displayed instead of the actual, some message cant be read as it seems to be applied as white color format, and my pst cant be opened up..I've tried disabling the office communicator, the snag it and for the past 2 hrs - it has been smooth! Will report back if it turns out otherwise later on...keeping fingers crossed!

  • I can tell you by your screenshot that the SnagIt addon was the cause of your Outlook problem. The same happens here at my firm with it enabled.

  • Hi ppl, i had a bit differenet problem, it's was not caused by an addon.. same happened in safe mode.. tryed lots of tools but nothing helped.. after about 20 seconds of running outlook used to make a long waves of 100% cpu load and then release.. and the same again and again.. no scanninig or repairing would help.
    i've understood it was something in the PST file..
    the simpliest resolution was just by adding a new storage file.. and moving everything into it. it was very simple and quick and solved the problem. i've set the new one to be default, removed the old one at all and just updated the Rules to the new folders.
    was so frastrated by this problem that when solved it, just had to to share! :)


  • Thanks Xrenix - your advice about PST file really helped!

  • This thread was really helpful. I was having a similar problem. The CPU usage was 100% the moment outlook was started. This happened about a month back after the download got interrupted. I could not open the attached files. The problem persisted till today when i decided to look for help. Disabling addons didn't help. I copied the pst file and deleted it from the system and started the outlook. Obviously it stopped half way through. I recopied the same file with a differnt name and made it the default data file. It had worked like magic. The CPU usage now is 2-4%. I hope it will remain like this.

  • Disabled all the com add-ins and the performance is much improved! Thanks!!

  • Thanks for the article. I disabled the Microsoft VBA for Outlook Addin and OneNote Notes about Outlook items and my cpu usage dropped instantly.

  • Great stuff! worked first time by removing ad-aware addin. I can run that seperately later but this was a pain in the bum...so slow...thanks very much indeed.

  • unchecked ad-aware email scanner. cpu usage down from 55% to 4%. thanks for to all advice.

  • great, Xobni had Outlook working @50%. after disabling went down to 2-4%

  • i hear everyone say they deleted the .pst.

    When I check the app data folder, i see that the archive file is a .pst while the outlook file is a .ost.

    Which one are you deleting and renaming to solve the problem.

  • worked for me ! Thanks..now if only someone could help me resolve my RTVscan... :) wishful thinking :)

  • Also all still have problems, Cached mode can cause this issue, may be worth disabling that and see if it drops ;)

  • Great tip! Removed the add-ins and CPU usage dropped from 50% (100% of one processor) to 0-5% usage.
    Thanks! :-)

  • I had the same CPU problem, tried all the above ideas with no success.

    Finally I managed to solve it by removing all the pst files and connecting them back again.

    While outlook is closed, you right click the outlook icon and press Properties ---> Data Files, than remove all the pst files except your default file.
    click ok and open outlook to check if cpu usage droped, if it did, close outlook, right click the outlook icon, Properties, Data Files (just like you did before, now add one pst file, click ok, open outlook and check cpu usage, repeat this until you add your last pst file.

    1. You need to make sure you know the exact location of you pst files (can be multiple locations)

    2. The reason that I added back the pst files one by one was to recognize if I have a damaged file.
    If you cpu usage jumps up after adding a pst file, try to use pst repair tools that can be found on the net.

    I hope I helped to some of you guys ;-)
    Good luck

  • Tried much of the above to no avail. Removed Follow Up Flags and CPU dropped from 26% to 1%.

  • For me, I removed the yahoo e-mail from Data Files. It's not pulling yahoo e-mail from server anyway.

    Here's what I did:
    While outlook is closed, right click the outlook icon and press Properties ---> Data Files. Find the one belong to Yahoo (which shows not working), highlight it and click "remove".

  • Thanks for the info!! Really helped me, I too found that deleting some emails with large attachments solved my issue.

  • excellent, it works!

  • Thanks for this useull post. Solved my problem!

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